Refrigeration compressor



May 1, 1962 Filed Feb. 15, 1960 R. CULK REFRIGERATION COMPRESSOR 5 Sheets-Sheet 1 y 1962 R. CULK v 3,032,257

REFRIGERATION COMPRESSOR Filed Feb. 15, 1960 5 Sheets-Sheet FIG. 5

May 1, 1962 R. CULK REFRIGERATION COMPRESSOR 5 Sheets-Sheet 5 Filed Feb. 15, 1960 May 1, 1962 R. CULK 3,032,257

REFRIGERATION COMPRESSOR Filed Feb. 15, 1960 s Sheets-Sheet 4 May 1, 1962 R. CULK REFRIGERATION COMPRESSOR 5 Sheets-Sheet 5 Filed Feb. 15, 1960 tates Unite The present invention relates to a refrigeration compressor which, together with the rotor of an electric motor, is mounted within a gas-tight casing which consists of a thin-walled hood enclosing the rotor with the smallest possible play and of a housing, preferably extended conically to contain the compressor, which housing is tightly sealed by means of a cover.

When assembling motor compressors of this type, care must be taken that the air space between the hood and the rotor, which air space is necessary to achieve a high degree of efficiency, is as small as possible.

In order to ensure the necessary reciprocal centring of the compressor cylinder carrying the rotor and the hood enclosing the rotor, it has already been proposed to construct a fixed part of the compressor, preferably the compressor cylinder, with a neck mounted co-axially with the rotor shaft, which neck projects into a collar-shaped projection mounted on the housing which contains the compressor, to which projection the rim of the hood is fixedly connected (see German specification No. 847,452). This form of construction has, however, the disadvantage that only the centring of the compressor cylinder is undertaken in the rim of the hub or in the collar-shaped projection on the housing, whilst, on the other hand, the compressor cylinder is secured far below i.e. in the housing containing the compressor, which results in the occurrence of a distortion or alteration in position between the compressor cylinder together with the rotor and the gas-tight casing, due to the pressures prevailing in the hood and in the housing, and due, above all to the heat stresses between the hood, which consists of chromenickel steel, and the housing which consists of sheet metal. This leads to the rotor rubbing against the internal wall of the hood.

The centring of the compressor cylinder only at the rim of the hood, or in the collar-shaped projection on the housing therefore affords no guarantee that a small air space will be maintained between the hood and the rotor.

According to a further proposal for the manufacture of refrigeration compressors of this kind, the housing, is made in one piece together with the hood, is of thinwalled construction and is provided, on that portion containing the compressor, with a supporting ring for securing the radially projecting rim of a plate carrying the compressor, and a cover to provide a seal for the opening in the housing opposite the motor, through which cover there pass the suction pipe and pressure pipe of the compressor, being placed on a rim flange of the housing to provide a tight seal (see US. Patent No. 2,629,542). According to this type of construction, the centring and securing of the compressor, together with the rotor, is carried out on a supporting ring which is located in the extended lower portion of the housing, so that the rotating masses of the rotor and of the rotor shaft are disposed far from their bearing position. This is, however, disadvantageous, since the slightest alteration in position of the supporting ring in relation to the housing, in consequence of the heat stresses and difierences in pressure occurring in the housing, results in the rotor rubbing against the inner wall of the housing part forming the hood. Thus this type of compressor construction demands, of necessity, a greater air space than would be necessary to achieve a high degree of electrical efliciency.

atent ice Furthermore to manufacture from one piece so tall a housing consisting of chrome-nickel steel is very difficult and expensive, also, the use of a supporting ring together with a bearer plate increases the total cost of the compressor to an extent which is unacceptable for cheap mass production.

The disadvantages mentioned are obviated according to the invention by both centring and securing a fixed compressor part, for example the compressor support-bearing flange, to the intermediary section of the housing which is located between the narrower housing on the hood side and the widened housing on the cover side. This has the advantage that the centring and securing of the compressor are carried out in common at a position located inside the gas-tight casing, which position is as near as possible to the rotating masses of the rotor, and of the counterweight, etc., so that, in spite of the heat stresses and pressure differences in the casing, the maintenance of a very small air space between rotor and hood is ensured. Furthermore, the securing screws, retaining bolts or the like, which may be used as securing and centring means, are so cheap in large numbers that they do not appreciably increase the total costs of production of the refrigeration compressor.

One object of the invention is to provide an assembly comprizing an electric motor, a gas-tight container part of which is cylindrical and surrounds the rotor of the motor, the stator of the motor being coaxially fixed around the cylindrical part of the container, a compressor suitable for compressing refrigerant, the compressor being fixed in the container, a shaft connecting the rotor with the compressor so that the former can drive the latter, means securing the compressor to the inner face of the container wall and means adjacent to these securing means centering the rotor in the stator,

Further objects and advantages of the invention will become clear as the following illustrative description proceeds. In the description reference is made to the drawings forming part of the specification.

In FIGURES 1 to 10 the various possible methods of securing the compressor inside the casing are illustrated in section. FIGURES l, 3, 5, 7 and 9 show longitudinal sections along the lines I-I, III-III, V--V, VII-VII, and lXIX of FIGURES 2, 4, 6, 8 and 10, respectively, and FIGURES 2, 4, 6, 8 and 10 show transverse sections along the lines lIlI, IV-IV, VI-VI, VIII-VIII and X-X of FIGURES 1, 3, 5, 7 and 9, respectively, the compressor as illustrated is turned into the plane of the drawing in the longitudinal sections, whilst in the transverse sections the stator housing is omitted or illustrated only in part, for the sake of greater clarity.

According to FIGURES 1 and 2, the gas-tight casing or container which encloses the refrigeration compressor 14, together with the rotor 9 of an electric motor, consists of a hood 1, a housing 2 and a cover 4. The housing 2 is preferably constructed to widen conically and is composed of a cylindrical part 2' of the housing on the hood end, an intermediary section 2" and a housing jacket 2'" on the end closed by the cover. On the hood 1 is coaxially fixed the stator 10 of an electric motor, which stator is preferably enclosed by a stator housing 10'. In the intermediary section 2" of the housing 2, retaining bolts 6 are secured in gas-tight manner by welding or soldering in appropriate borings. At the end of the retaining bolts 6 located in the interior'of the housing is disposed a centring projection 6", which is machined in common with the inner surface of the hood 1 and of the cylindrical part 2' on the hood side, and to which a compressor cylinder 8, which is of one piece with a compressor-support frame 7, is secured by means of screws 5. The retaining bolts 6 project out beyond the outer surface of the intermediary section 2" of the housing 2,

and carry, by means of flanges the stator housing surrounding the stator 16 of the electric motor. The flanges 5" are secured on the retaining bolts 6 by means of screws 5 which, in an analogous manner to the screws 5, are screwed into threaded borings in the retaining bolts. In order to avoid gas losses, these threaded borings -do not run right through, but are blind. Furthermore, the retaining bolts 6 are also provided, at the ends located outside the housing 2, with a centring projection 6" which serves for the common machining of the centring projection 6" located inside the housing 2 and of the internal jacket surface of the hood 1.

Whilst, in the embodiment illustrated by way of example in FIGURES 1 and 2, the centring and securing of the compressor cylinder 8, together with the compressor-support frame 7, can be carried out indirectly at the transition section 2" of the housing 2 through the retaining bolts 6, it may be seen from FIGURES 3, 4 or 5, 6 that the compressor cylinder 8 or the compressor-support frame 7 can also be centrally secured directly to the transition or intermediary section 2 of the housing 2. For this purpose, step-shaped pressed-out sections 3 are provided, the internal surfaces 3 of which are machined in common with the internal surfaces of the hood I and of the part 2' of the housing on the hood side. According to FIGURES 3 and 4, the compressor cylinder 8 is directly secured in these pressed-out sections 3 by means of screws 50 which are inserted, from outside, into appropriate holes in the pressed-out sections 3, and seal the case housing outwardly in a gas-tight manner by means of the sealing rings 12. 7% denotes the compressor frame. In contrast to FIGURES 3 and 4, the pressed out sections 31, according to FIGURES 5 and 6, are bored, not to permit the passage of screws, but to receive retaining bolts 61, which are located in the pressed-out sections 31 from outside by means of an extension 61' of reduced cross section and which form a gas-tight fit'with the pressed out sections for example by welding or soldering. The face surface of the extension 61, which points into the interior of the housing 2, is machined in common with that inner surface 31' of the pressed out sections 31 to which the fixed compressor part, for example the compressor support frame 71, is secured by means of the screws 51. Since the inner surface of the hood I is also machined in common with the inner surface 31' of the pressed-out sections 3, an exact central position is ensured between a shaft 11 carrying a rotor 9 and the hood I enclosing the rotor 9.

The embodiment according to FIGURES 7 and 8 differs from that of FIGURES 5 and 6 in that the retaining bolt 62 is inserted from inside and by means of its exten sion 62, of reduced cross section, locates the holes in the pressed-out section 32, and'is provided, at its end projecting inwardly of the housing 2, with a centring projection 62. The centring and securing of the compressor-support frame 72 is thus carried out exclusively at the retaining bolts 62, so that the inner surface of the pressed-out sections 32 needs no machining. The gastight connection of the retaining bolts 6 with the pressedout sections 32 is produced by connecting the outwardly projecting extension 62' of the retaining bolt 62. to the outer surface of the pressed-out sections 32 by means of welding or riveting.

In FIGURE 7 there is indicated, in dotted lines, the

further possibility of giving the centring projection 62 superfluous. Centring projections 63" are provided for centring the compressor cylinder 3 at the securing bolts 63, whilst the compressor-support bearing flange 7 is itself again centred in an annular recess 73' in the compressor cylinder 8.

A method of centring and securing similar to that shown at the left-hand side of FIGURES 9 and 10 may be seen at the right hand side thereof, where the securing bolts 63 are secured in the pressed-out sections 33 from within by means of welding or soldering. This type of securing also aliows the threaded borings in the retaining bolts 63 to extend throughout the bolts.

After the refrigeration compressor 14, together with the rotor 9, has been centred and secured, according to one of the embodiments mentioned by way of example, in the casing consisting of the hood I and the housing 2, the lower rim of the housing jacket 2" on the cover end is connected to the downwardly bent rim portion of a cover 4 by means of a welded seam, in the known manner of encased refrigeration motors, which seam, in order to undertake repairs, may be easily removed by machining and, after the repairs, can be easily renewed on the rim which has not been appreciably shortened.

The invention is not limited to the embodiments illustrated by way of example in the drawings, since alternative means may be used for centring and securing, direct- 1y or indirectly, a fixed compressor part to the transition section of the housing'within the scope of the invention. Furthermore a reliable and gas-tight connection of all parts of the gas-tight container (housing, hood and cover) may be very easily achieved not only by welding but also by hard soldering in a protective gas atmosphere, it is therefore possible to make do with the simplest jigs and templates for welding or soldering the various retaining bolts so that very cheap mass production of the refrigeration compressor is possible.

I claim:

1. In combination, an electric motor with its rotor axis upright, a gas-tight container whose upper part is cylindrical and contains the rotor of the electric motor, the stator of the motor being coaxially fixed around this cylindrical part, the part of the container below the motor comprising a diverging intermediary portion and below this, a base portion of the container of greater width than the upper cylindrical part of the container, a compressor suitable for compressing refrigerant, this compressor being fixed in the base part of the container, a shaft connecting the rotor with the compressor so that the former can drive the latter, the shaft also supporting the rotor with which it is coaxial, a frame in the container supporting the compressor, bearing means on the frame rotatably supporting the rotor, abutment means in the region of the intermediary portion of the container and rigid with the cylindrical portion of the container, abutment means on the frame, the abutment means on the container engaging the abutment means on the frame so as to center the rotor in the stator, and means situated in the region of the abutment means, securing the frame to the container.

2. In combination, an electric motor with its rotor axis upright, a gas-tight container whose upper part is cylindrical and contains the rotor of the electric motor, the stator of the motor being coaxially fixed around this cylindrical part, the part of the container below the motor comprising a diverging intermediary portion and, below this, a base portion of greater width than the upper cylindrical part of the container, a compressor suitable for compressing refrigerant, this compressor being fixed in the base part of the container, a shaft connecting the rotor with compressor so that the former can drive the latter, the shaft also supporting the rotor with which it is coaxial, a frame in the container supporting the compressor, bearing means on the frame rotatably supporting the rotor, bolts passing through, and secured in a gas-tight manner in, holes in the intermediary portion of the container, these bolts having abutment faces engaging abutment faces on the frame so as to center the rotor in the stator, and screws screwed into holes in the bolts so as to secure the frame to them.

3. The structure as set forth in claim 2 in which the parts of the bolts on the outside of the container have faces corresponding to fragments of the surface of a cylinder concentric with the axis of the rotor; the structure also comprising a housing surrounding the stator, this housing being screwed to the bolts,

4. In combination, an electric motor with its rotor axis upright, a gas-tight container whose upper part is cylindrical and contains the rotor of the electric motor, the stator of the motor being placed around this cylindrical part, the part of the container below the motor comprising a diverging intermediary part pressed so that parts of its inner surface face radially inwards, the part of the container below this intermediary position being of greater width than the part of the container surrounding the rotor, a compressor in this part of the container, and being suitable for the compression of refrigerant, a shaft connecting the compressor with the rotor so that the latter can drive the former, a frame supporting the compressor and the rotor, this frame abutting against the above-mentioned inwardly facing surface parts of the diverging intermediary part of the container, so as to center the rotor in the stator, and means situated near the inwardly facing surfaces, securing the frame to the container.

5. The structure as defined in claim 4 in which inwardly facing surface parts against which the frame abuts are machined While near them there are screws securing to the frame to the container, the screws passing through the wall of the container so that their leads lie outside it.

6. The structure as set forth in claim 4, further comprising, screws passing through holes in the frame into holes in the intermediary portion of the container near the inwardly facing surface parts on the latter against which the frame abuts, bolts outside the container, these bolts having narrow portions passing into the holes in the intermediary portion of the container, the bolts engaging the container sealingly so as to prevent the egress of gas from the holes in the intermediary portion of the container and the screws being screwed into holes in the narrow portions of the bolts.

7. In combination, an electric motor with its rotor axis upright, a gas-tight container whose upper part is cylindrical and contains the rotor of the electric motor, the stator of the motor being coaxially fixed around this cylindrical part of the container, the part of the container below the motor comprising a diverging intermediary portion and below this is a base portion of the container of greater width than the upper cylindrical part of the container, a compressor suitable for compressing refrigerant, this compressor being fixed in the base part of the container, a shaft connecting the rotor with the compressor so that the former can drive the latter, the shaft also supporting the rotor with which it is coaxial, a frame in the container supporting the compressor, bearing means fixed to the frame and rotatably supporting the rotor, bolts fixed to the inwardly turned face of the intermediary portion of the container, these bolts having abutment faces in contact with the frame thus serving to center the rotor of the motor in the stator, and screws securing the frame to the bolts, the screws passing into holes in the bolts.

8. The structure as set forth in claim 7 in which projecting peg-like portions on the bolts pass into holes in the wall of the intermediary portion of the container.

9. The structure as set forth in claim 7 in which the bolts are welded to the inner face of the intermediary portion of the container.

References Cited in the file of this patent UNITED STATES PATENTS 1,263,633 Zoelly Apr. 23, 1918 FOREIGN PATENTS 847,452 Germany Aug. 25, 1955 

